1. Field of the Invention
The present invention relates to a flexible display apparatus (hereinafter, also simply referred to as a display apparatus) which is thin, light in weight, and large in screen size. In particular, the present invention relates to a display apparatus which can be rolled up or bent (folded) to be stored.
2. Description of the Related Art
Currently, the demands for thin display apparatuses represented by a liquid crystal display (LCD) and an organic electroluminescence (EL) display has been rapidly increasing. However, further reductions in thickness and weight have been required in the market. It is desired to realize a flexible display apparatus in the near future. The flexible display apparatus has a large screen, but is thin and light in weight, so the apparatus can be rolled up or bent. Therefore, the flexible display apparatus can be easily held and carried. However, in the flexible display apparatus, there arise problems involving dropping or impact while being carried and friction or wearing between contact surfaces thereof while being rolled up or bent for storage, which do not occur in the conventional display apparatuses.
Conventionally, a glass base film is used for the display apparatus such as the LCD and the organic EL display. The flexible display apparatus requires reductions in thickness and weight, an increase in screen size, improvements in impact resistance characteristic and flexible characteristic, so a base film material thereof has been mainly reviewed.
When the glass base film is used, reinforcing a conventional glass material to reduce a thickness thereof has been studied (see Japanese Patent Application Laid-Open No. 2005-019082).
Also, employing one of a polymer film and a metal thin film instead of the glass base film has been studied (see Japanese Patent Application Laid-Open Nos. 2000-012213, 2004-281086, S62-103998 and H07-282980).
Further, a base film in which the glass and the polymer film are combined has been studied (see Japanese Patent Application Laid-Open Nos. 2004-079432 and 2006-024530).
However, even when the glass base film is thinned, there is a problem with respect to the impact resistance characteristic. In addition, it is impossible to bend the glass base film without being broken up to a level to which the glass base film is rolled up (with a diameter of, for example, 100 mm) to be stored.
When one of the polymer film and the metal thin film is used as the base film, there is no problem with respect to reductions in thickness and weight, an increase in screen size, an improvement in flexible characteristic, and the like. However, the inventor of the present invention found that, when a light emitting surface is brought into contact with an opposed surface while the base film is being rolled up or bent to be stored, there arises a problem in the light emitting surface because the light emitting surface is easily damaged.